Predicting areas important for ecological connectivity throughout Canada.

Governments around the world have acknowledged that urgent action is needed to conserve and restore ecological connectivity to help reverse the decline of biodiversity. In this study we tested the hypothesis that functional connectivity for multiple species can be estimated across Canada using a single, upstream connectivity model. We developed a movement cost layer with cost values assigned using expert opinion to anthropogenic land cover features and natural features based on their known and assumed effects on the movement of terrestrial, non-volant fauna. We used Circuitscape to conduct an omnidirectional connectivity analysis for terrestrial landscapes, in which the potential contribution of all landscape elements to connectivity were considered and where source and destination nodes were independent of land tenure. Our resulting map of mean current density provided a seamless estimate of movement probability at a 300 m resolution across Canada. We tested predictions in our map using a variety of independently collected wildlife data. We found that GPS data for individual caribou, wolves, moose, and elk that traveled longer distances in western Canada were all significantly correlated with areas of high current densities. The frequency of moose roadkill in New Brunswick was also positively associated with current density, but our map was not able to predict areas of high road mortality for herpetofauna in southern Ontario. The results demonstrate that an upstream modelling approach can be used to characterize functional connectivity for multiple species across a large study area. Our national connectivity map can help governments in Canada prioritize land management decisions to conserve and restore connectivity at both national and regional scales.

Integrating carbon stocks and landscape connectivity for nature-based climate solutions.

Actions to protect against biodiversity loss and climate change will require a framework that addresses synergies between these interrelated issues. In this study, we present methods for identifying areas important for the implementation of nature-based climate solutions and biodiversity conservation by intersecting high-resolution spatial data for carbon storage and landscape connectivity. We explored the spatial congruence of carbon and connectivity in Ontario, Canada and examined effectiveness of current protected areas coverage. We found a weak positive relationship between carbon stocks and landscape connectivity; however, our maps revealed large hotspots, with high values of both indices, throughout the boreal forest and northern peatlands and smaller, isolated hotspots, in the settled landscapes of the south. Location of hotspots varied depending on whether we considered forest or soil carbon. Further, our results show that current protected and conserved areas in Ontario only cover 13% of landscapes with the highest values for both carbon storage and connectivity. Protection or restoration of areas that maximize the co-benefits of carbon storage and connectivity would make significant contributions toward ambitious national targets to reduce greenhouse gas emissions and conserve biodiversity.

Clinical experience with polygenic risk score in subjects with early cognitive concerns.

BACKGROUND: There is mounting evidence that lifestyle interventions and behavioural changes play a significant role in maintaining cognition and function, as well as preventing dementia. Consequently, it is important that clinicians confronted with subjects with early cognitive concerns, have appropriate tools available to assist in diagnosis and to facilitate risks management appropriately. The application of polygenic risk score (PRS) tests has the potential to contribute towards management planning and to reduce the burden of testing in subjects with low overall risk. METHODS: This retrospective analysis considered the application of genoSCORETM in a small cohort of patients seen over a six month period in a London Memory Clinic. The test was offered to selected patients in the clinic with MCI not clinically attributable to dementia, or cognitively normal individuals concerned about their risks of dementia. The impact upon clinical management and lifestyle modification was reviewed. genoSCORE, a polygenic risk score algorithm, was developed by Cytox to assess genetic risk for the future development of Late-Onset Alzheimer's disease (LOAD). RESULTS: Patients receiving the genoSCORE test included those with early MCI, subjective memory complaints and a small number concerned about their risk of dementia. In each case, a medical history was taken and individuals assessed using the Addenbrooke's Cognitive Examination, conducted either in clinic or remotely. genoSCORE polygenic risk score was easy to conduct and well received. The results stimulated individuals at risk of developing LOAD to make lifestyle adjustments and thereby potentially modifying their dementia risk. CONCLUSIONS: In this study, the genoSCORE PRS test provided a valuable assessment of genetic risk of individuals most likely to decline cognitively decline towards AD and as such, contributed significantly to clinical management decisions. The ease and effectiveness of home sampling of saliva as source DNA for the PRS test was a major factor and well aligned with the continuing need for remote consultations in the light of COVID-19 concerns. Further larger-scale studies to determine the full clinical and associated economic impact of the genoSCORE PRS test are required.

Polygenic score prediction captures nearly all common genetic risk for Alzheimer's disease.

We estimate the maximum prediction accuracy for the risk of Alzheimer's disease based on disease prevalence and heritability of liability. We demonstrate that the recently reported AUC values for predicting of Alzheimer's disease using polygenic scores reach about 90% of the estimated maximum accuracy that can be achieved by predictors of genetic risk based on genomic profiles.

An estrogen-platinum terpyridine conjugate: DNA and protein binding and cellular delivery.

A platinum metal complex in which terpyridine joins estradiol (via an ethynyl link) to a platinum with a labile ligand (chloride) has been designed, synthesised and its X-ray crystal structure determined. The aim of this work was to link a targeting motif (in this case estrogen) to a metal-based biomolecule recognition unit (the platinum moiety). The target molecule: 17alpha-[4'-ethynyl-2,2':6',2'-terpyridine]-17beta-estradiol platinum(II) chloride (PtEEtpy) has been shown to bind to both human and bovine serum albumin (SA) and to DNA. FTICR mass spectrometry shows that the bimolecular units are in each case linked through coordination to the platinum with displacement of the chloride ligand. Circular dichroism indicates that a termolecular entity involving PtEEtpy, SA and DNA is formed. A range of electrospray mass spectrometry experiments showed that the PtEEtpy complex breaks and forms coordination bonds relatively easily. A whole cell estrogen receptor assay in an estrogen receptor positive cell (MCF-7) confirms binding of both EEtpy and PtEEtpy to the estrogen receptor in cells. The work demonstrates the concept of linking a targeting moiety (in this case estrogen) to a DNA binding agent.

PET and the role of in vivo molecular imaging in personalized medicine.

In order for personalized medicine to become a clinical reality a number of hurdles, both technological and regulatory in nature, need to be addressed. Our ability to image biological and pathological processes at a molecular level using positron emission tomography (PET) imaging offers an unparalleled opportunity to radically reform the manner in which a disease is diagnosed and managed. The degree to which current innovations in PET science will translate into clinical practice, thereby impacting upon personalized medicine, is discussed.

In vivo imaging of human colon cancer xenografts in immunodeficient mice using a guanylyl cyclase C--specific ligand.

UNLABELLED: Guanylyl cyclase C (GC-C) is a transmembrane receptor expressed by human intestinal cells and primary and metastatic colorectal adenocarcinomas but not by extraintestinal tissues or tumors. The Escherichia coli heat-stable enterotoxin analog, STa (5--18), is a 14--amino acid peptide that selectively binds to the extracellular domain of GC-C with subnanomolar affinity. This study examined the utility of a radiolabeled conjugate of STa (5--18) to selectively target and image extraintestinal human colon cancer xenografts in vivo in nude mice. METHODS: The STa conjugate, ethoxyethyl-mercaptoacetamidoadipoylglycylglycine-STa (5--18) (NC100586), was synthesized and labeled with (99m)Tc to produce (99m)Tc-NC100586. This compound was intravenously administered to nude mice bearing human colon cancer xenografts, and specific targeting was evaluated by biodistribution and gamma camera imaging. RESULTS: In CD-1 nude mice, biodistribution and scintigraphic imaging analyses showed selective uptake of (99m)Tc-NC100586 into human colon cancer xenografts that express GC-C but not into normal tissues that do not express GC-C. Similarly, (99m)Tc-NC100586 injected intravenously into CD-1 nude mice with human colon cancer hepatic metastases selectively accumulated in those metastases, and about 5-mm foci of tumor cells were visualized after ex vivo imaging of excised livers. Accumulation of (99m)Tc-NC100586 in human colon cancer xenografts reflected binding to GC-C because (99m)Tc-NC100588, an inactive analog that does not bind to GC-C, did not selectively accumulate in cancer xenografts compared with normal tissues. Also, coadministration of excess unlabeled STa (5--18) prevented accumulation of (99m)Tc-NC100586 in human colon cancer xenografts. Furthermore, (99m)Tc-NC100586 did not selectively accumulate in Lewis lung tumor xenografts, which do not express GC-C. CONCLUSION: This study showed that intravenously administered STa (5--18) selectively recognizes and binds to GC-C expressed by human colon cancer cells in vivo. Also shown was the ability to exploit this selective interaction to target imaging agents to extraintestinal human colon tumors in nude mice. These results suggest the utility of STa and GC-C for the development of novel targeted imaging and therapeutic agents with high specificity for metastatic colorectal tumors in humans.